6. Project Summary/Abstract Little is known about the rate and pattern of change in Neurocognitive skills among abstaining youth with histories of heavy drinking. Decades of research on adult alcohol dependence has shown that substantial improvements in neuropsychological (NP) functioning unfold during the early weeks of abstinence and may extend for years. Since adolescent alcohol use may more adversely affect neurocognitive processes than adult exposure, examination of improvement in NP skills and the neuroanatomical underpinnings and behavioral correlates of such changes is merited. The present study seeks to: 1) develop and refine methodology critical to examination abstention related changes in NP skills and neuroanatomical functioning among adolescents, and 2) conduct a pilot study of such changes comparing abstaining, former heavy drinking 16-18 year olds (>100 lifetime alcohol episodes, recent high dose drinking and withdrawal symptoms) to matched nondrinking peers over 6 weeks of monitored abstention. The methods development and refinement stage (Phase I) uses new technology to continuously assess abstinence (via transdermal alcohol monitor) and remotely conduct experience sampling (text messaging and activity logs) of potential moderators of NP change (affect, sleep, activities), and evaluates feasibility of repeated NP/Behavioral testing at 2,4, and 6 wks. Phase II pilots the full NP, behavioral and neuroimaging (MRI, fMRI, DTI) protocol on a sample of 55 heavy drinking adolescents who are abstaining over a 6 week time period and 20 matched nondrinking peers. Changes in NP skills, and neuroanatomical structure and functioning will be examined along with proposed moderators of such change and potential behavioral correlates of NP improvement (driving skills, risk taking, cue reactivity, and school participation). Linear mixed[unreadable]effects models will be used to: 1) examine hypotheses regarding greater NP improvement and neuroanatomical changes among abstaining heavy drinkers relative to controls, 2) ascertain predictive power of proposed moderators of NP change, and 3)explore relations between NP skills and developmentally relevant behavioral functioning. Results will serve as a foundation for RO1 to more fully evaluate abstinence-related NP recovery of youth. 7. Project Narrative Relevence, Alcohol consumption during adolescence is becoming an increasing problem in the U.S. with 78% of youth drinking before they even finish high school and the majority of high school seniors who drink exhibiting one or more alcohol problems. Research now indicates that adolescent brains may be more vulnerable to the effects of alcohol than adults and little is known about improvement in cognitive functioning when teens become abstinent. The present study examines the extent to which thinking abilities of adolescents with heavy drinking histories improve in the first six weeks of abstinence. The study also examines underlying brain changes and predictors and correlates of cognitive improvement.